Cooling spot-welding electrode.



EJH'OMSON.

COOLING SPOT WELDING ELECTRODE.

mum/mou FILED my 2s. mi.

1,256,951. Patente@ @6b. H1918.

w @i minuto@ UNITED sTATEs PATENT oEEIoE.

ELIHU THOMSON, OF SWAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO THOMSON SPOT WELDER. COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHU- lCOOLING SPOT-WELDING ELECTRODE.

To all whom it may concern Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident of Swampscott, in the county of Essex and State of Massachusetts, have invented: certain new and useful Improvements in Cooling Spot-Welding ElectrodesA` of which the following is a specification.

My invention relates to the manner of cooling electrodes of thatclass of electric welding machines. in which the electrode, owing to the fact that it is in -direct contact with the portion of'work being welded, is liable to become unduly heated so that it is necessary or desirable to provide some means for artificially cooling.; said electrode. necessity for 'a provision of this character is experienced particularly with the electrodes of spot welders and for this reason it has been heretofore proposed to circulate a cooling liquid such as water through the electrode. nary conditions it may, by the sudden or extreme heating of the end of the electrode `near the work,'be thrown into Vspheroidal state and fail to carry off the heat'properly. This is particularly true even with copper electrodes when they are employed for large '1 electrode itself goes, my invention is capable and heavy work. i

The object of`my invention is to'overcome this difficulty in the ease of electrodes of copper and also to permit the use of mate .rial stiifer and harder than copper for the electrode by providing eiiicient cooling therefor even though the same may become heated to a veryhigh temperature. I

By the use of my invention a nickel electrode may be used. w 1

Essentially my invention consistsin circulating through' the electrode a liquid, like water, restricting the flow thereof and 'maintaining a pressure of the 1i uid in tthe heated part of the electrode vsu cient to prevent the liquid from being thrown into the spheroid'al state by the excessive heat."

In practice 4I propose'to keep the liquid i at a high pressure ofseveral hundred pounds or even as-high as-one thousand pounds to the square inch. To accomplishthis it may be pumped into the electrode at the desired pressure and permitted to escape 'through .aV

safety valve set to maintain t at pressure. In this case the liquid could not enter' into the spheroidal stateeven at a very high temperature of the electrode. l

The

If water is circulated under ordi- Specication of Letters Patent. Patnted Feb.l 19, 1918. Application med my 2s, 1917.

Serial N0. 171,634.

Thepressure required` would necessarily vary with the conditions.' Ail/ordinary atmospheric pressure it is ywell known that the lsurface-heated to that temperature breaks' and even at pressures considerably above the atmospheric pressure, such as may occur when the attempt is made to keep the temperature down by supplyin the liquid and simply circulating it in su .cient volume to carry off the heat, the spheroidal state will occur and defeat the object of efficient cooling when the metal reaches the very high temperatures which are liable to be produced in electric welding electrodes during use.

In my invention I do not depend upon rapidity of the fiow of the-liquid but on the contrary aim to restrict the flow for economys sake and secure the desired result of efficient cooling by insuring contact of the liquid with the metal surfaces by maintaining a pressure well above that at which the liquid c'ould be thrown into the spheriodal state under any of the temperatures to which the electrode may be subjected and this pressure I call s uper-pressure.wv Y

Plainly, so far as the structure of the through a safety valve set to maintain the desired high pressure. The liquid may escape as superheated water or be converted into steam or be a mixture of steam and water when it escapes.

In the accompanying drawings the figure is an elevation and partial section of the apparatus to which my invention is applied. The circulation of liquid is shown as employed only in connection with the upper Yelectrode 1 of the spot Welder although, as

will be readily understood, the cir'cu ation of the. liquid mioht be continued through the electrode 2' if tdesired.. 3 indicates a pi e connected with the source from which e water or similar liquid is supplied under the i zing at its lower end into the space within the electrode proper.

5 indicates a pipe connected with the spaces within the stem 6 to which theelectrode l is attached, such spaces communicating with the space in the electrode 1 into which the pipe 4 delivers the li uid. 7 indicates any safety or pressure va ve inserted in the outlet passages and adjusted as before stated to maintain the required pressure.

What I claim as my invention is f 1. The improvement in cooling electrodes of electric welding machines by a cooling liquid, consisting 1n restricting the ow of the liquid and maintaining said liquid in contact with the surfaces to be A'cooled at a super-pressure t0 prevent the liquid from bethe electrode proper, consisting in restricting the flow of the Water and maintaining it at a super-pressure within the electrode so as to prevent it from being thrown into the spheroidal state.

Signed'at Lynn in the county of Essex andy 1' State of Massachusetts this 14th day of May A.' D. 1917. Y

= ELIHU THOMSLON. Vgitnesses:

F. B. TowNsEND, IRENE Lnrxowrrz'. 

